Substrate bonding method

Abstract

A substrate bonding method includes: preparing a first substrate having a first silicon oxide film with a film thickness of 50 nm or more arranged on the first substrate, and a second substrate having a second silicon oxide film arranged on the second substrate; bonding the first substrate and the second substrate together in a state where the first silicon oxide film and the second silicon oxide film face each other; and heating and bonding the first substrate and the second substrate. The preparing of the first substrate and the second substrate includes preparing the second substrate having the second silicon oxide film with a film thickness of 2.5 nm or less. The heating and bonding of the first substrate and the second substrate includes heating the first substrate and the second substrate at a temperature of 200° C. or more and 800° C. or less.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This application is a U.S. national stage application of International Patent Application No. PCT / JP2016 / 001025 filed on Feb. 25, 2016 and is based on Japanese Patent Applications No. 2015-47504 filed on Mar. 10, 2015, and No. 2016-14852 filed on Jan. 28, 2016, the disclosures of which are incorporated herein by reference.TECHNICAL FIELD[0002]The present disclosure relates to a substrate bonding method for bonding a first substrate having a first silicon oxide film formed on a surface of the first substrate and a second substrate having a second silicon oxide film formed on a surface of the second substrate to each other.BACKGROUND ART[0003]Up to now, as disclosed in Patent Literature 1, a method of manufacturing an SOI wafer in which two silicon wafers are bonded together has been known. First, an oxide film is formed on both of the silicon wafers. Then, the silicon wafers are bonded together through the oxide film. The silicon wafers ha...

AI Technical Summary

Benefits of technology

The present disclosure provides a substrate bonding method that prevents a reduction in bonding strength without heating at a high temperature. This is achieved by setting the film thickness of the first silicon oxide film to 50 nm or more to absorb any generated water, and the film thickness of the second silicon oxide film to 2.5 nm or less to allow for a lower heating temperature. Overall, this method ensures strong bonding between the substrates without the need for high temperature heating.

Problems solved by technology

Therefore, in a method of heating at the high temperature described above, the SOI wafer cannot be manufactured.

However, in the bonding method, when the silicon wafers are bonded together, no oxide films can be formed on both of the silicon wafer surfaces.

On the other hand, in the above configuration, since the oxide film cannot be formed on both of the silicon wafer surfaces, the out-diffusion may occur, and the interface level may become large.

Further, in the above-described configuration in which the oxide film cannot be formed on both of the silicon wafer surfaces, the degree of freedom in designing the SOI wafer may decrease.

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